The striker has signed a four-year contract after four-and-a-half years with the Hammers where he scored 39 goals in all competitions following his transfer from Tottenham in January 2004.
Injury hampered 27-year-old Zamora last season and he was restricted to just 12 starts and only one goal.
He told the club's official website: "I am delighted that we have reached an agreement to enable me to play for Fulham next season.
"I am looking forward to joining the rest of the team this week and preparing for the new campaign.
"This is a new challenge for me and the prospect of working with a coach of Roy Hodgson's calibre was a great opportunity, so I am excited at the prospect of competing for a regular place in the team."